ntpd could probably be rewritten to use it, which probably makes more sense than doing pty redirection. Well, secretly I guess "rewritten" is actually "a gpsd input module".

That's true. That would make more sense...add a specific NMEA-gpsd module/driver. I'll have to find the source of the existing NMEA to see if I can make any sense of it...possibly an interesting learning experience in between those scarce job interviews!

Isn't ntp 4 just "ntp" again and not "xntp"? Or are you really still using ntp 3?

You're correct. It was just Jim's very fuzzy logic at work again. And what *was* that "X" about anyway?!?